Abstract [en]

The invention relates to an onboard warning system for a host vehicle (1), a system comprising a sensor system detecting a presence of external objects (2) within a sensor detection area (3) and an external object movement determination unit (5) arranged to determine a measure of a relative movement of said external objects to said host vehicle. The invention is characterized in that the warning system further includes: a host vehicle movement determination unit (4) arranged to determine a relative movement of said host vehicle to a ground-fixed coordinate system; a unit (6) for determination of a measure of a absolute acceleration of said external objects to said ground-fixed coordinate system by transformation of the measure of the relative movement of said external objects to said host vehicle into said ground-fixed coordinate system using the relative movement of said host vehicle determined by said host vehicle movement determination unit; and a warning signal generator (7) arranged to generate a warning signal when said measure of absolute acceleration of said external objects relative to said fixed ground acceleration system in the sensor detection area exceeds a threshold value.